The invention relates to a process for producing an immobilized enzyme preparation for use in a mainly organic medium essentially devoid of free water, and use of the immobilized enzyme preparation for organic synthesis.
Immobilized enzymes are known to be used for organic synthesis.
The most commonly immobilized enzymes are lipases used for esterification reactions in mainly organic media essentially devoid of free water.
EP 140542 B2 describes a process, wherein an enzyme containing liquid is brought in contact with a weak anion exchange resin carrier by dispersing the carrier in the liquid and mixing by stirring with a magnetic stirrer, whereby the enzyme is immobilized on the carrier. The immobilization is subsequently followed by vacuum drying of the enzyme-carrier.
WO 95/22606 describes a process, wherein an enzyme containing liquid is brought in contact with a porous silica carrier by atomizing the liquid onto the carrier in a mixer, subsequently followed by drying overnight at ambient conditions.
In industrial immobilization processes described in prior art, the carrier or support material is placed in a column shaped adsorption vessel and an enzyme containing liquid is recirculated until sufficient adsorption of the enzyme on the carrier has been obtained. Following the adsorption step the column is emptied by manually shoveling the enzyme-carrier product into trays. The product is then dried by placing the trays under vacuum at room temperature for a period of 14-16 hours.
WO 94/26883 describes a process for producing dust-free enzyme granules by absorbing the enzyme on a porous material, said material including NaCl, Soda, and silica, and optionally coating the product with a protective outer layer. Generally immobilization of enzymes should not be compared with granulation of enzymes as granulation serves a completely different purpose, viz. to provide a preferably non-dusting delivery material from which an enzyme may be delivered to an aqueous solution by disintegration of the granule and/or dissolution of the enzyme in the aqueous phase. Enzyme immobilization concerns immobilizing an enzyme product on a carrier on which the enzyme is fixed and yet functional and for which the enzyme is not liberated to the solvent to which it is applied.
Immobilization processes known to the art are limited in capacity as they involve laborious and manual steps and require heavy equipment investments (e.g. vacuum rooms), which, in turn, means inflexible production and expensive products.
The present invention provides alternative processes for industrial immobilization of enzymes, which significantly increases capacity and reduces labor costs, by means of standard multi-purpose process equipment.
Thus the invention provides processes for producing an immobilized enzyme preparation for use in a mainly organic medium essentially devoid of free water, which in a first aspect comprises:
a) fluidizing a particulate porous carrier in a fluid bed,
b) introducing an enzyme containing liquid medium by atomization into the fluid bed, so as to adsorb the enzyme on the carrier, and
c) removing volatile components of the liquid medium from the carrier in the fluidized bed.
In a second aspect the process comprises:
a) contacting an enzyme containing liquid medium with a particulate porous carrier having a substantially hydrophobic surface, so as to adsorb the enzyme on the carrier,
b) introducing a particulate hygroscopic substance, so as to suppress agglomeration of the carrier, and
c) removing volatile components of the liquid medium and the hygroscopic substance from the resulting product in a fluidized bed.
Finally in a third aspect the process comprises:
a) introducing an enzyme containing liquid medium by atomization onto a particulate porous carrier having a substantially hydrophilic surface, so as to adsorb the enzyme on the carrier, wherein the liquid is introduced in an amount such that substantially no agglomeration of the carrier occurs and
b) removing volatile components of the liquid medium from the resulting product in a fluidized bed.